- Insertion of Diazo Esters into C-F Bonds toward Diastereoselective One-Carbon Elongation of Benzylic Fluorides: Unprecedented BF3Catalysis with C-F Bond Cleavage and Re-formation
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Selective transformation of C-F bonds remains a significant goal in organic chemistry, but C-F insertion of a one-carbon-atom unit has never been established. Herein we report the BF3-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C-F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF3 catalyst could contribute to both C-F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.
- Wang, Fei,Nishimoto, Yoshihiro,Yasuda, Makoto
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supporting information
p. 20616 - 20621
(2021/11/23)
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- Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
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An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
- Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
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supporting information
p. 12643 - 12646
(2021/12/07)
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- 3,3′-Disubstituted Oxindoles Formation via Copper-Catalyzed Arylboration and Arylsilylation of Alkenes
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Arylboration and arylsilylation reactions of N-(2-iodoaryl)acrylamides with bis(pinacolato)-diboron (B2pin2) or PhMe2Si-Bpin are developed by using simple CuOAc as the sole catalyst. A range of boron-or silane-bearing 3,3′-disubstituted oxindoles are obtained in moderate to excellent yields. The reaction is proposed to proceed via a domino sequence involving intermolecular olefin borylcupration or silylcupration followed by intramolecular coupling of an alkyl-Cu intermediate with aryl iodide.
- Liang, Ren-Xiao,Chen, Ru-Yi,Zhong, Chao,Zhu, Jia-Wen,Cao, Zhong-Yan,Jia, Yi-Xia
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supporting information
p. 3215 - 3218
(2020/04/10)
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- Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
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The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
- Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
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supporting information
p. 9982 - 9992
(2020/06/27)
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- Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation
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A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.
- Zhu, Qilei,Nocera, Daniel G.
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supporting information
p. 17913 - 17918
(2020/12/04)
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- Dehydroxymethylation of alcohols enabled by cerium photocatalysis
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Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
- Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
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supporting information
p. 10556 - 10564
(2019/08/20)
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- Dehydroxymethylation of Alcohols Enabled by Cerium Photocatalysis
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Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
- Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
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supporting information
p. 10556 - 10564
(2019/08/28)
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- Iridium-Catalyzed α-Methylation of α-Aryl Esters Using Methanol as the C1 Source
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IrCl(cod)2]/dppe-catalyzed α-methylation of aryl esters using methanol as the C1 source was developed. This methylation process is useful in several fields including organic chemistry, biochemistry, and medicinal chemistry. Readily available methanol as methylation reagent was successfully adapted. The reaction processed high atom economy and efficient. By applying the reaction system, the synthesis method of naproxen was provided.
- Tsukamoto, Yuya,Itoh, Satoshi,Kobayashi, Masaki,Obora, Yasushi
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supporting information
p. 3299 - 3303
(2019/05/10)
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- Synthesis and bio-evaluation of natural butenolides-acrylate conjugates
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A series of novel 3-aryl-4-hydroxy-2(5H) furanone-acrylate hybrids were designed and synthesized based on the natural butenolides and acrylates scaffolds. The structures of the prepared compounds were characterized by 1H-NMR, 13C-NMR and electrospray ionization mass spectrometry (ESI-MS), and the bioactivity of the target compounds against twelve phytopathogenic fungi was investigated. The preliminary in vitro antifungal activity screening showed that most of the target compounds had moderate inhibition on various pathogenic fungi at the concentration of 100 mg·L?1, and presented broad-spectrum antifungal activities. Further studies also indicated that compounds 7e and 7k still showed some inhibitory activity against Pestallozzia theae, Sclerotinia sclerotiorum and Gibberella zeae on rape plants at lower concentrations, which could be optimized as a secondary lead for further research.
- Bao, Longzhu,Wang, Shuangshuang,Song, Di,Wang, Jingjing,Cao, Xiufang,Ke, Shaoyong
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- Palladium-Catalyzed C?H Silylation through Palladacycles Generated from Aryl Halides
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A highly efficient palladium-catalyzed disilylation reaction of aryl halides through C?H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C?H activation, including C(sp2)?H, C(sp3)?H, and remote C?H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane-bridged biphenyls.
- Lu, Ailan,Ji, Xiaoming,Zhou, Bo,Wu, Zhuo,Zhang, Yanghui
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supporting information
p. 3233 - 3237
(2018/02/23)
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- Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
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A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
- Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 555 - 559
(2018/02/21)
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- Pd-Catalyzed Three-Component Domino Reaction of Vinyl Benzoxazinanones for Regioselective and Stereoselective Synthesis of Allylic Sulfone-Containing Amino Acid Derivatives
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A Pd-catalyzed, highly regioselective and stereoselective three-component domino allylic substitution/N-H carbene insertion reaction under mild conditions is described. This reaction demonstrates a wide substrate scope and satisfactory functional group tolerance, providing a broad range of allylic sulfone-containing amino acid derivatives. Moreover, DBU mediates highly diastereoselective cross-dehydrogenative coupling annulation of allylic sulfones without using peroxides or any metal oxidants. This developed protocol affords 7-membered ring heterocyclic compounds incorporating both sulfone-containing amino acid esters and one quaternary carbon center. Mechanistic studies indicate that an unusual umpolung of glycine occurred in this annulation.
- Hao, Jiping,Xu, Yi,Xu, Zhongliang,Zhang, Zhiqiang,Yang, Weibo
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supporting information
p. 7888 - 7892
(2019/01/04)
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- A sustainable procedure toward alkyl arylacetates: Palladium-catalysed direct carbonylation of benzyl alcohols in organic carbonates
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A sustainable procedure for the synthesis of various alkyl arylacetates from benzyl alcohols has been developed. With palladium as the catalyst and organic carbonates as the green solvent and in situ activator, benzyl alcohols were carbonylated in an efficient manner without any halogen additives.
- Li, Yahui,Wang, Zechao,Wu, Xiao-Feng
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supporting information
p. 969 - 972
(2018/03/13)
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- The computer-aided discovery of novel family of the 5-HT6 serotonin receptor ligands among derivatives of 4-benzyl-1,3,5-triazine
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The work describes a discovery of new chemical family of potent ligands for the 5-HT6 serotonin receptors. During the search for new histamine H4 receptor antagonists among 1,3,5-triazine derivatives, compound 2 (4-benzyl-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine) was found. Compound 2, weakly active for the H4 receptor but fitted in 3/4 of pharmacophore features of the 5-HT6R ligand, occurred to be a moderate 5-HT6R agent, useful as a lead structure for further modifications. A series of new derivatives (3–19) of the lead 2 was synthesized, evaluated in the radioligand binding assay (RBA) and explored in comprehensive molecular modelling, including both pharmacophore- and structure-based approaches with docking to the homology model of 5-HT6R. The most active compounds displayed a potent affinity for the 5-HT6R in the nanomolar range (Ki?=?20–30?nM), some of them (4, 11 and 19) were tested in the rat forced swim test that revealed their antidepressant-like effect. SAR-analysis on the basis of both, RBA and docking results, indicated that action on the receptor is related to the hydrophobicity and the size of aromatic moiety substituted by a methylene linker at the position 4 of 1,3,5-triazine.
- ?a?ewska, Dorota,Kurczab, Rafa?,Wi?cek, Ma?gorzata,Kamińska, Katarzyna,Sata?a, Grzegorz,Jastrz?bska-Wi?sek, Magdalena,Partyka, Anna,Bojarski, Andrzej J.,Weso?owska, Anna,Kie?-Kononowicz, Katarzyna,Handzlik, Jadwiga
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supporting information
p. 117 - 124
(2017/04/26)
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- Synthesis and evaluation of essential oil-derived β-methoxyacrylate derivatives as high potential fungicides
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Essential oils (EOs) are plant-derived aroma compounds with a wide range of biological activity, but their actions are slow, and they are typically unstable to light or heat, difficult to extract and so on. To find highly potential fungicides derived from natural EOs, a series of essential oil-based β-methoxyacrylate derivatives have been designed and synthesized. The target compounds have been screened for their potential fungicidal activity against eleven species of plant pathogen fungi, including Alternaria alternata, Phomopsis adianticola, Pestalotiopsis theae, Sclerotinia sclerotiorum, etc. Compared with intermediates I, the parent essential oils and azoxystrobin, almost all of essential oil-based β-methoxyacrylate derivatives exhibited significantly better fungicidal activity. Further investigation revealed that some compounds showed remarkable inhibitory activities against Pestalotiopsis theae, Phomopsis adianticola, Sclerotinia sclerotiorum and Magnapothe grisea at different concentrations in contrast to the commercial product azoxystrobin. Compound II-8 exhibited particularly significant fungicidal activity.
- Su, Haihuan,Wang, Wenda,Bao, Longzhu,Wang, Shuangshuang,Cao, Xiufang
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- Water as a Hydride Source in Palladium-Catalyzed Enantioselective Reductive Heck Reactions
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Pd-catalyzed intramolecular asymmetric carbopalladation of N-aryl acrylamides followed by reduction of C(sp3)-Pd intermediate using diboron–water as a hydride source afforded enantioenriched 3,3-disubstituted oxindoles in high yields and enantioselectivities. When heavy water was used as a deuterium donor in combination with bis(catecholato)diboron (Cat2B2), deuterium was incorporated into the products with high synthetic efficiency. The ligand determined both the enantioselectivity of the reaction and the reaction pathways, thereby affording either hydroarylation (reductive Heck) or carboborylation products.
- Kong, Wangqing,Wang, Qian,Zhu, Jieping
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supporting information
p. 3987 - 3991
(2017/03/27)
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- An approach to spirooxindoles: Via palladium-catalyzed remote C-H activation and dual alkylation with CH2Br2
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A facile and efficient approach for the synthesis of spirooxindoles has been developed via the coupling of spirocyclic C,C-palladacycles with CH2Br2. The key spirocyclic palladacycles are generated catalytically via remote C-H activation. A range of spirooxindoles can be synthesized in good to excellent yields from readily available starting material.
- Shao, Changdong,Wu, Zhuo,Ji, Xiaoming,Zhou, Bo,Zhang, Yanghui
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supporting information
p. 10429 - 10432
(2017/09/25)
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- One-Carbon Homologation of Primary Alcohols to Carboxylic Acids, Esters, and Amides via Mitsunobu Reactions with MAC Reagents
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A method is reported for the one-carbon homologation of an alcohol to the extended carboxylic acid, ester, or amide. The process involves the Mitsunobu reaction with an alkoxymalononitrile, followed by unmasking in the presence of a suitable nucleophile. The homologation and unmasking can even be performed in a one-pot process in high yield.
- Kagawa, Natsuko,Nibbs, Antoinette E.,Rawal, Viresh H.
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supporting information
p. 2363 - 2366
(2016/06/09)
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- Ring Expansion of Epoxides under Br?nsted Base Catalysis: Formal [3+2] Cycloaddition of β,γ-Epoxy Esters with Imines Providing 2,4,5-Trisubstituted 1,3-Oxazolidines
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A novel ring-expansion reaction of epoxides under Br?nsted base catalysis was developed. The formal [3+2] cycloaddition reaction of β,γ-epoxy esters with imines proceeds in the presence of triazabicyclodecene (TBD) as a superior Br?nsted base catalyst to afford 2,4,5-trisubstituted 1,3-oxazolidines in a highly diastereoselective manner. This reaction involves the ring opening of the epoxides with the aid of the Br?nsted base catalyst to generate α,β-unsaturated esters having an alkoxide at the allylic position, which would formally serve as a synthetic equivalent of the 1,3-dipole, followed by a cycloaddition reaction with imines in a stepwise fashion. This methodology enables the facile synthesis of enantioenriched 1,3-oxazolidines from easily accessible enantioenriched epoxides.
- Kondoh, Azusa,Odaira, Kenta,Terada, Masahiro
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supporting information
p. 11240 - 11244
(2016/07/06)
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- Synthesis and antifungal potential of 1,2,3-triazole and 1,2,4-triazole thiol substituted strobilurin derivatives
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β-Methoxyacrylate group is an important pharmacophore of commercially used strobilurin fungicides. In the present study, a total of seventeen 1,2,4-triazole thiols 8a-h and 1,2,3-triazole substituted 10a-i strobilurin derivatives have been synthesized. 1,2,4-Triazole thiol substituted strobilurin derivatives 8a-h have been found to inhibit the growth of plant pathogens such as Fusarium oxysporum, Magnaporthe grisea, Drechslera oryzae and human pathogens Aspergillus fumigatus and different strains of Cryptococcus neoformans, with MIC in the range of 16-256 μg/mL. In case of Candida albicans tested strain, the MIC is > 256 μg/mL. p-Chlorophenyl substituted 1,2,4-triazole thiol strobiulrin derivative 8e is the most potent inhibitor with MIC of 16-64 μg/mL against most of the tested pathogens. Antifungal action of the compounds is due to inhibition of mitochondrial respiration. In the resazurin reduction assay, EC50 for inhibition of RZ reduction in D. oryzae by azoxystrobin and 8e are 3.42±0.03 μg/mL and 3.63±0.21 μg/mL, respectively; while in case of C. neoformans, EC50 of azoxystrobin and 8e are between 0.65-0.85 μg/mL. In a non-pathogenic model Benjaminiella poitrasii, though the MIC for all the synthesized compounds 8a-h and 10a-i are > 256 μg/ml, yeast to hypha transition is inhibited in the range of 21-75% at 4 μg/mL concentration while EC50 for inhibition of RZ reduction by azoxystrobin and 8e are 31.5±0.4 μg/mL and 17.95 ± 0.7 μg/mL, respectively. The 50% germ tube formation inhibition in case of C. albicans is observed at 108.49 μg/mL. 1,2,4-Triazole thiol substituted strobilurin derivatives hold promise for the control of pathogenic fungi in agriculture and health care.
- Chaudhary, Preeti M.,Tupe, Santosh G.,Jorwekar, Shweta U.,Sant, Duhita G.,Deshpande, Sunita R.,Maybhate, Shailaja P.,Likhite, Anjali P.,Deshpande, Mukund V.
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p. 908 - 917
(2015/08/18)
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- Higher-order cyclopropenimine superbases: Direct neutral br?nsted base catalyzed michael reactions with α-aryl esters
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The synthesis and characterization of six new classes of higher-order superbases, including five that incorporate cyclopropenimine functionality, has been achieved. We propose a nomenclature that designates these as the CG2, GC2, PC3, PC1, C3, and GP2 classes of superbases. The pKBH+ values were measured to be between 29.0 and 35.6 in acetonitrile. Linear correlations of ten superbase basicities vs that of their substituents demonstrated the insulating effect of the cyclopropenimine core. The molecular structures of several of these materials were obtained by single-crystal X-ray analysis, revealing interesting aspects of conformational bias and noncovalent organization. The types of superbasic cores and substituents were each reliably shown to affect selectivity for deprotonation over alkylation. Higher-order cyclopropenimine and guanidine superbase stability to hydrolysis was found to correlate to basicity. Finally, a GC2 base was found to catalyze conjugate additions of α-aryl ester pronucleophiles, representing the first report of a neutral Br?nsted base to catalyze such reactions.
- Nacsa, Eric D.,Lambert, Tristan H.
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supporting information
p. 10246 - 10253
(2015/09/01)
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- Copper(II)-acid catalyzed cyclopropanation of 1,3-dienamides by electrophilic activation of α-aryl diazoesters
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Copper(II)-acid catalyzed cyclopropanation of electron-rich alkenes, such as 1,3-dienamides, with α-aryl diazoesters are described. The reaction could be performed without rare metal catalysts, excess substrate, or the need for the slow addition of the diazoesters.
- Tayama, Eiji,Horikawa, Kouki,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information
p. 3041 - 3044
(2014/05/20)
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- Tripeptidic BACE1 inhibitors devised by in-silico conformational structure-based design
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Previously reported pentapeptidic BACE1 inhibitors, designed using a substrate-based approach, were used as lead compounds for the further design of non-peptidic BACE1 inhibitors. Although these peptidic and non-peptidic inhibitors, with a hydroxymethylcarbonyl isostere as a substrate transition-state mimic, exhibited potent BACE1 inhibitory activities, their molecular-sizes appeared a little too big (molecular weight of >600 daltons) for developing practical anti-Alzheimer's disease drugs. To develop lower weight BACE1 inhibitors, a series of tripeptidic BACE1 inhibitors were devised using a design approach based on the conformation of a virtual inhibitor bound to the BACE1 active site, also called 'in-silico conformational structure-based design'. Although these tripeptidic BACE1 inhibitors contained some natural amino acid residues, they are expected to be useful as lead compounds for developing the next generation BACE1 inhibitors, due to their low molecular size and unique structural features compared with previously reported inhibitors.
- Hamada, Yoshio,Tagad, Harichandra D.,Nishimura, Yoshinori,Ishiura, Shoichi,Kiso, Yoshiaki
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scheme or table
p. 1130 - 1135
(2012/03/26)
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- Novel ether-functional spiro-tetronic acid derivatives: Molecule design, convenient synthesis and biological evaluation
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A novel series of ether functionalization of spiro-tetronic acid derivatives have been designed and conveniently synthesized via three steps, including esterification, one-pot heterocyclization, and etherification reactions. The target molecules have been identified on the basis of analytical spectra data. All newly synthesized compounds have been screened for their potential insecticidal activity against Heliothis armigera and Plutella xylostella compared with spirodiclofen by standard method. Springer Science+Business Media B.V. 2012.
- Ke, Shaoyong,Zhang, Zhigang,Zhang, Ya-Ni,Shi, Liqiao,Zhou, Ronghua,Jiang, Aibing,Liang, Ying,Yang, Ziwen
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p. 1827 - 1837
(2013/02/22)
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- A METHOXYL ACRYLIC ESTER FUNGICIDE, THE PREPARATION METHOD AND USES THEREOF
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A methoxyl acrylic ester fungicide, the preparation method and uses thereof. The fungicide contains at less the following compound of formula (I) as active ingredient. The fungicide can be further prepared to form the emulsifier oil by mixing with the emulsifier, latent solvent, stabilizer, and solvent. The fungicide is useful for preventing and controlling powdery mildew, downy mildew, gray mold and tan discase of vegetable, melon and fruit, discase of vegetable, melon and fruit cased by Phoma citricarpa, leaf spot of maize, false smut, blossom-end rot of orange and Sclerotinia rot of colza et al. The fungicide has many advantages such as be effect to the strain which produced the resistance, high effect, less toxic and environmrnt-friendly.
- -
-
Page/Page column 3; 4
(2011/04/24)
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- Microwave-assisted synthesis of 5-substituted 2-aminothiophenes starting from arylacetaldehydes
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An easy three-step pathway for the synthesis of arylacet-aldehydes from the corresponding carboxylic acids in very high yields is described. Their use as precursors of 5-substituted-2-aminothiophenes is illustrated via a microwave-assisted Gewald reaction. This method allows obtaining the expected compounds in a shorter time and with better yields and purities than the classical procedures. Georg Thieme Verlag Stuttgart - New York.
- Revelant, Germain,Dunand, Sandrine,Hesse, Stephanie,Kirsch, Gilbert
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experimental part
p. 2935 - 2940
(2011/11/01)
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- METHOXYACRYLATE-BASED FUNGICIDE AND METHODS FOR PREPARING AND USING THE SAME
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A pharmaceutical composition of fungicide including at least a compound represented by Formula (I). The pharmaceutical composition of fungicide can further include an emulsifier, a cosolvent, a stabilizer, and a solvent. The fungicide can prevent and treat powdery mildew, downy mildew, gray mold, brown spot, scab of vegetables and fruits, southern leaf blight of corn, rice false smut, citrus stem-end rot, and rape sclerotinia rot, with high efficiency, low toxicity, and relative environmental friendliness. A method of preparing the fungicide and a method of using thereof are also provided.
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Page/Page column 3
(2010/12/18)
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- Spirodiclofen analogues as potential lipid biosynthesis inhibitors: A convenient synthesis, biological evaluation, and structure-activity relationship
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Twenty spirodiclofen analogues have been designed and conveniently synthesized via three steps including esterification, one-pot heterocyclization, and acylation reactions. The target molecules have been identified on the basis of analytical spectra (1H NMR, 13C NMR and ESI-MS) data. All newly synthesized compounds have been screened for their potential insecticidal and herbicidal activity by standard method. The preliminary assays indicated that some of analogues displayed moderate to good insecticidal activity against Plutella xylostella compared with spirodiclofen, and some compounds showed obvious activity against Brassica chinensis. Structure-activity relationship (SAR) is also discussed based on the experimental data.
- Ke, Shaoyong,Sun, Tingting,Zhang, Zhigang,Zhang, Ya-Ni,Liang, Ying,Wang, Kaimei,Yang, Ziwen
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experimental part
p. 2315 - 2321
(2010/11/16)
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- Synthesis and biological activity of novel phenyltriazolinone derivatives
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Phenyltriazolinones are one of the most important classes of herbicides targeting the protoporphyrinogen oxidase enzyme. A series of triazolinone derivatives containing a strobilurin pharmacophore were designed and synthesized with the aim of discovering new phenyltriazolinone analogues with high activity. The herbicidal activity of the synthesized compounds was assayed and some of the test compounds displayed moderate herbicidal activity at 150 g ai/ha.
- Wu, Qiongyou,Wang, Guodong,Huang, Shaowei,Lin, Long,Yang, Guangfu
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scheme or table
p. 9024 - 9034
(2011/03/20)
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- Regioselective arene functionalization: Simple substitution of carboxylate by alkyl groups
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Arenes with various alkyl side-chains were synthesized in high yields and excellent regioselectivities. Starting from toluic and naphthoic acids, the carboxylate group was conveniently substituted by alkyl halides by Birch reduction and subsequent decarbonylation. The method is characterized by inexpensive starting materials and reagents, and methylation of arenes was realized. Besides simple alkyl substituents, the scope of arene functionalization was extended by benzyl, fluoro, amino, and ester groups. We were able to control the alkylation of 1-naphthoic acid during Birch reduction by the addition of tert-butanol. This allowed the regioselective synthesis of mono and bis-substituted naphthalenes from the same starting material.
- Krueger, Tobias,Vorndran, Katja,Linker, Torsten
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experimental part
p. 12082 - 12091
(2010/05/17)
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- Oxidative rearrangements of arylalkanones with 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide, a 'green' analog of Koser's reagent
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Previous methods for the conversion of arylalkanones to alkyl 2-arylesters by oxidative rearrangement utilized reagents which either produced toxic metal salts or halogenated organics as by-products. In this report, 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide (HMBI) is used to effect this useful transformation, where the reduced iodine reagent is water-soluble and readily recycled.
- Justik, Michael W.
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p. 3003 - 3007
(2008/02/06)
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- γ-methylidene-δ-valerolactones as a coupling partner for cycloaddition: Palladium-catalyzed [4 + 3] cycloaddition with nitrones
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A new type of reagent, γ-methylidene-δ-valerolactones, has been devised, which acts as a four-carbon unit in a palladium-catalyzed cycloaddition reaction through the formation of a 1,4-zwitterionic species. The utility has been demonstrated in the context of stereoselective [4 + 3] cycloaddition with nitrones to provide highly functionalized 1,2-oxazepines, including the asymmetric variant with high enantioselectivity. Copyright
- Shintani, Ryo,Murakami, Masataka,Hayashi, Tamio
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p. 12356 - 12357
(2008/03/27)
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- NOVEL ADENINE COMPOUND AND USE THEREOF
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A drug for topically administration which is effective as an antiallergic agent. The drug for topically administration contains as an active ingredient an adenine compound represented by the general formula (1): [wherein ring A represents a 6 to 10 membered, mono or bicyclic, aromatic hydrocarbon or a 5 to 10 membered, mono or bicyclic, aromatic heterocycle containing one to three heteroatoms selected among 0 to 2 nitrogen atoms, 0 or 1 oxygen atom, and 0 or 1 sulfur atom; n is an integer of 0 to 2; m is an integer of 0 to 2; R represents halogeno, (un)substituted alkyl, etc.; X1 represents oxygen, sulfur, NR1 (R1 represents hydrogen or alkyl), or a single bond; Y1 represents a single bond, alkylene; etc.; Y2 represents a single bond, alkylene, etc.; Z represents alkylene; and at least one of Q1 and Q2 represents -COOR10 (wherein R10 represents (un)substituted alkyl, etc.), etc.] or a pharmaceutically acceptable salt of the compound.
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Page/Page column 28
(2010/02/12)
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- Fungicidal compounds having a fluorovinyl-or fluoropropenyl-oxyphenyloxime moiety and process for the preparation thereof
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A fungicidal compound of formula (I) having a fluorovinye- or fluoropropenyl-oxyphenyloxime moiety and stereoisomers thereof are useful for protecting crops from fungal diseases: wherein, X is CH or N; Y is O or NH; R1is hydrogen, C1-4alkyl, or halogen-substituted C1-4alkyl, R2is a phenyl group optionally carrying one or more substituents selected from the group consisting of C1-4alkyl, C1-4alkoxy, methylenedioxy and halogen; or a naphthyl group; and R3is hydrogen or CF3.
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- Fungicidial compounds having a fluorovinyloxphyenyl moiety and process for the preparation thereof
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A fungicidal compound of formula (I) having a fluorovinyloxyphenyl moiety and stereoisomers thereof are useful for protecting crops from fungal diseases: wherein: X is CH or N; Y is O or S; Z is O or NH; R1is hydrogen or CF3; and R2is hydrogen, a C1-10alkyl, naphthyl, thiophenyl or a phenyl group optionally carrying one or more substituents selected from the group consisting of C1-6alkyl, halogen-substituted C1-6alkyl, C1-6alkoxy, phenoxy, halogen, and methylenedioxy radicals.
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- Selective ET(A) antagonists. 5. Discovery and structure-activity relationships of phenoxyphenylacetic acid derivatives
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The fifth paper in this series describes the culmination of our investigations into the development of a potent and selective ETA receptor antagonist for the treatment of diseases mediated by ET-1. Receptor site mapping of several ETA antagonists prepared previously identified a common cationic binding site which prompted synthesis of phenoxyphenylacetic acid derivative 13a, which showed good in vitro activity (IC50 59 nM, rat aortic ET(A)). Optimization of 13a led to the identification of 27b, which exhibited an IC50 of 4 nM. Although this did not translate into the expected in vivo potency, a compound of comparable in vitro activity, 27a (RPR118031A), showed a far better pharmacokinetic profile and in vivo potency (75 μmol/kg) and was duly proposed and accepted as a development candidate.
- Astles, Peter C.,Brown, Thomas J.,Halley, Frank,Handscombe, Caroline M.,Harris, Neil V.,Majid, Tahir N.,McCarthy, Clive,McLay, Lain M.,Morley, Andrew,Porter, Barry,Roach, Alan G.,Sargent, Carol,Smith, Christopher,Walsh, Roger J. A.
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p. 900 - 910
(2007/10/03)
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- Regioselectivity of the Base-Induced Ring Cleavage of 1-Oxygenated Derivatives of Cyclobutabenzene
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Oxy anions 3 generated from 1,2-dihydrocyclobutabenzen-1-ones 1 through addition of a charged nucleophile or from 1-hydroxy-1,2-dihydrocyclobutabenzenes 2 by deprotonation with base lead to stable products through distal and/or proximal cleavage of the strained four-membered ring via benzyl carbanion 4 and/or aryl carbanion 5. A systematic study of this process reveals the relative stability of the two isomeric carbanions 4 and 5 as a key factor in determining the course of the ring-cleavage reaction. While benzyl carbanions 4 can be trapped with carbon electrophiles, attempts at trapping aryl carbanions 5 with electrophiles other than H+ failed. In protic solvents, the magnesium salt of the tertiary alcohol 2 shows an increased rate of proximal cleavage as compared to its alkali salts. From this, we conclude that, in contrast to benzyl carbanions 4, free aryl carbanions 5 are of transient existence only. Proximal C,C-bond cleavage seems to occur either through protonation of 5 from a fast, reversible equilibrium 3?5 in which 3 strongly predominates, or in protic solvents possibly even through a rate-limiting protonation of 3 at the aromatic C-atom, bypassing free anion 5 altogether. Thus, additional factors other than just the relative stability of isomeric carbanions 4 and 5 are of importance in determining the regiochemistry of the base-induced C,C-bond cleavage in ketones 1 and in alcohols 2.
- Gokhale, Abha,Schiess, Peter
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p. 251 - 267
(2007/10/03)
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- Manufacture of arylacetic acids and their esters
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Arylacetic acids and their esters, of the formula Ar(CH2 -COOR)n (where Ar=aryl, R is H or a hydrocarbon radical, and n is 1 or 2) are manufactured by carbonylation of halomethylaryl compounds Ar(CH2 C)n (where X is Cl, Br or I) with carbon monoxide and a catalyst m+ ?Fe(O)3 NO!- (where M is an alkali metal, ammonium or one equivalent of an alkaline earth metal) in the presence of stoichiometric amounts of an inorganic base or of an alcoholate of an alcohol ROH.
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- Conversion of Aromatic Ketones into α-Arylalkanoic Acids. Oxidation by Thallium(III) and by Halogens
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The mechanism by which thallium (III) nitrate oxidises aromatic ketones to α-arylalkanoic acids has been investigated and the role of additives in the system elucidated.It is found that in the absence of additives an organothallium intermediate, most probably the phenacylthallium species BzCH2Tl(NO3)2, persists and that the key to an efficient rearrangement is the ready conversion of this compound into its acetal.Thallium(III) is shown not to be a unique reagent for the oxidation.Other oxidants capable of acting initially as an electrophile and then as a leaving group are equally effective, provided that formation of an acetal is possible.Iodine-silver nitrate in particular offers considerable advantages as reagent over thallium(III).Higher specificity is achieved, unwanted side-reactions can be avoided, and toxicity problems are eliminated.Bromine may be used instead of iodine, but chlorine proves unsatisfactory as an oxidant.
- Higgins, Stanley D.,Thomas, Barry C.
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p. 235 - 242
(2007/10/02)
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